[css-align] Fix the Values section to be more up-to-date. Fixes #1397.

Author: tabatkins

css-align/Overview.bs

@@ -90,16 +90,13 @@ Module interactions</h3>
 Values</h3>
 
 	This specification follows the <a href="https://www.w3.org/TR/CSS21/about.html#property-defs">CSS property definition conventions</a> from [[!CSS2]].
-	Value types not defined in this specification are defined in CSS Level 2 Revision 1 [[!CSS2]].
-	Other CSS modules may expand the definitions of these value types:
-	for example [[CSS3VAL]], when combined with this module,
-	adds the ''initial'' keyword as a possible property value.
+	Value types not defined in this specification are defined in CSS Values & Units [[!CSS-VALUES-3]].
+	Other CSS modules may expand the definitions of these value types.
 
 	In addition to the property-specific values listed in their definitions,
-	all properties defined in this specification also accept the
-	<a href="https://www.w3.org/TR/CSS21/cascade.html#value-def-inherit">inherit</a>
-	keyword as their property value. For readability it has not been repeated
-	explicitly.
+	all properties defined in this specification
+	also accept the <a>CSS-wide keywords</a> keywords as their property value.
+	For readability they have not been repeated explicitly.
 
 <h3 id="partial">
 Partial Implementations</h3>